scholarly journals Direct Digital Manufacturing of Nanocomposites

2019 ◽  
Vol 890 ◽  
pp. 92-97
Author(s):  
Saeed D. Mohan ◽  
Meruyert Nazhipkyzy ◽  
Pedro Carreira ◽  
Cyril Santos ◽  
Fred J. Davis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Additive Manufacturing ◽  
Digital Manufacturing ◽  
Polymer Devices ◽  
Automated Process ◽  
Mechanical Performances ◽  
Direct Digital Manufacturing

Additive manufacturing has surged in popularity as a route to designing and preparing functional parts. Depending on the parts function, certain attributes such as high mechanical performances may be desired. We develop a route for improving the mechanical properties of polymer devices, fabricated through additive manufacturing by combining electrospinning and stereo-lithography into one automated process. This process utilises the impressive mechanical properties of carbon nanotubes by encapsulating and aligning them in electrospun fibres. Composite fibres will be incorporated into polymer resins prepared with stereo-lithography, thereby providing resins that benefit from the composite fibres properties, enhancing their overall mechanical properties.

Complex Sparse-Filled Mechanical Property Prediction Methods for Direct Digital Manufacturing

2013 ◽  
Author(s):  
David N. Kordonowy ◽  
Sydney A. Giblin
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Flexible Manufacturing ◽  
Test Methods ◽  
Low Noise ◽  
Digital Manufacturing ◽  
Cycle Times ◽  
Mechanical Property Prediction ◽  
Direct Digital Manufacturing ◽  
And Control

This paper describes how direct digital manufacturing mechanical properties can be analytically estimated for structural use and the associated analytical and test methods used in the design and fabrication of airframes manufactured using additive manufacturing. Complex shape structures, which are now possible using additive manufacturing, and their associated mechanical properties can be predicted in order to allow operationally safe and highly predictive structures to be fabricated. Direct digital manufacturing allows for much greater flexibility and control over the design of airframes, leading to more structurally efficient and capable airframes. These advantages are revealed by application of direct digital manufacturing methods on a series of fixed wing subsonic transport concept wind tunnel scale models that are carried out as a part of the NASA N+3 program, which is paving the way for next generation aircraft that are highly fuel efficient, low-noise, and low-emission. Verification of these methods through test shows excellent correlation that provides reliability in complex sparse filled additive manufacturing design. The outcome of this is a knowledge base, which can then be applied to a system in operation. The combined potential of a flexible manufacturing system and proven predictive analysis tools shorten development time and expand the opportunities for mass customization. These combined benefits enable industry to fabricate affordable highly optimized custom products while concurrently reducing the cycle times required to field new products.

A NOVEL, SCALABLE PRODUCTION OF MULTIFUNCTIONAL NANOCOMPOSITE POLYMER FILAMENTS FOR ADDITIVE MANUFACTURING

2021 ◽  
Author(s):  
MIA CARROLA ◽  
AMIR ASADI
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Additive Manufacturing ◽  
Aqueous Suspension ◽  
Manufacturing Method ◽  
Nanocomposite Polymer ◽  
Water As Solvent ◽  
Materials Used ◽  
Scalable Production

Though a revolutionary process, additive manufacturing (AM) has left more to be desired from printed parts, specifically, improved interlayer strength and minimal defects such as porosity. To overcome these common issues, nanocomposites have become one of the most popular materials used in AM, with various nanoparticles used to achieve a variety of characteristics. The use of these technologies together allows for both to synergistically enhance the final printed parts by improving the process and products simultaneously. Here, we introduce a novel, scalable technique to coat ABS pellets with cellulose nanocrystal (CNC) bonded carbon nanotubes (CNT), to improve the adhesion between layers as well as the mechanical properties of printed parts. An aqueous suspension of CNT-CNC is used to coat ABS pellets before they are dried and extruded into filament for printing. The filament produced using this manufacturing method showed an increase in tensile and interlayer strength as well as improved thermal conductivity. This process uses water as solvent and pristine nanoparticles without the need for any functionalization or surfactants, promoting its scalability. This process has the potential to be used with various polymers and nanoparticles, which allows the materials to be specifically tailored to the end application, (i.e. strength, conductivity, antibacterial, etc.). These nanocomposite filaments have the potential to revolutionize the way that additive manufacturing is utilized in a variety of industries.

A high-speed additive manufacturing approach for achieving high printing speed and accuracy

2019 ◽  
Vol 234 (14) ◽  
pp. 2741-2749 ◽  
Author(s):  
Aamer Nazir ◽  
Jeng-Ywan Jeng
Keyword(s):  
Additive Manufacturing ◽  
Material Property ◽  
High Speed ◽  
Selective Laser Sintering ◽  
High Accuracy ◽  
Digital Manufacturing ◽  
Functional Material ◽  
Direct Digital Manufacturing ◽  
Manufacturing Technologies ◽  
Printing Speed

The primary concern of the Industry 4.0 is the direct digital manufacturing of customized products on demand at high production speed, high accuracy with functional material property. Although the unique capabilities of existing additive manufacturing technologies make it suitable for direct digital manufacturing, there are numerous limitations which include low printing speed, less accuracy and repeatability, and a limited selection of materials for a particular application. Therefore, a high-speed additive manufacturing approach is proposed in this paper, that is capable of achieving high speed of production, high accuracy, and surface finish, and functional material property. For better understanding, authors describe those additive manufacturing technologies that are capable of achieving the aforementioned characteristics. For validation, samples of various dimensions were 3D printed on a selective laser sintering and a high-speed multijet fusion 3D printer. The results were compared in the context of printing speed, surface roughness (Ra), and hardness of printed parts. Results revealed that the multijet fusion process is significantly faster than its counterpart while sacrificing Ra to some extent but the hardness of printed parts is not changed significantly. The selective laser sintering-printed samples had a 15% lower Ra compared with multijet fusion samples. The results also revealed that the multijet fusion process might be able to print composite/multi-materials; however, more research needs to be done.

scholarly journals Study of mechanical behavior of additive manufacturing bioresorbable polymeric stents models

2020 ◽  
pp. 38-51
Author(s):  
Adriana DM Del Monaco ◽  
MI Del Monaco ◽  
Aron JP Andrade ◽  
Sonia Maria Malmonge
Keyword(s):  
Mechanical Properties ◽  
Lactic Acid ◽  
Additive Manufacturing ◽  
Aortic Coarctation ◽  
Polymeric Materials ◽  
Memory Allocation ◽  
Interesting Point ◽  
Allocation Process ◽  
Artery Disease ◽  
Mechanical Performances

Stents are devices with important applications in cardiology. They can be used in different cases, as coronary artery disease, peripheral interventions, such as the iliac and carotid arteries, and in very specific applications, as congenital heart disease in aortic coarctation. Studies point to biodegradability of stents as one of the main properties of future generations of these devices. The development of stents made from fully bioresorbable polymeric materials, with appropriate mechanical properties for different applications, is considered an interesting point to be studied. Thus, the objective of this project was to study models of bioabsorbable stents of poly (-L-lactic acid) (PLLA), poly (-LD lactic acid) (PLDLA) produced by additive manufacturing. The mechanical performances were evaluated by stress and tensile strain tests of different blends compositions of these materials. A heatshock shape memory allocation process and a flexible tube model for simulating implant conditions were developed. PLLA has higher mechanical strength and hardness, while PLDLA is more elastic. Thus, it was possible to study the adequacy of the composition and mechanical properties of the prototypes for each different situation studied (coronary, peripheral and Aortic coarctation implants).

scholarly journals Customized Fabrication Approach for Hypertrophic Scar Treatment: 3D Printed Fabric Silicone Composite

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Lung Chow ◽  
Kit-Lun Yick ◽  
Mei-Ying Kwan ◽  
Chun-Fai Yuen ◽  
Sun-Pui Ng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Three Dimensional ◽  
Adhesive Force ◽  
Digital Manufacturing ◽  
Pressure Therapy ◽  
Remarkable Improvement ◽  
Print Materials ◽  
3D Printed ◽  
Direct Digital Manufacturing ◽  
Manufacturing Technologies

Hypertrophic scars (HS) are considered to be the greatest unmet challenge in wound and burn rehabilitation. The most common treatment for HS is pressure therapy, but pressure garments may not be able to exert adequate pressure onto HS due to the complexity of the human body. However, the development of three-dimensional (3D) scanning and direct digital manufacturing technologies has facilitated the customized placement of additively manufactured silicone gel onto fabric as a component of the pressure therapy garment. This study provides an introduction on a novel and customized fabrication approach to treat HS and discusses the mechanical properties of 3D printed fabric reinforced with a silicone composite. For further demonstration of the suggested HS therapy with customized silicone insert, silicone inserts for the finger webs and HS were additively manufactured onto the fabric. Through the pressure evaluation by Pliance X system, it proved that silicone insert increases the pressure exerted to the HS. Moreover, the mechanical properties of the additively manufactured fabric silicone composites were characterized. The findings suggest that as compared with single viscosity print materials, the adhesive force of the additively manufactured silicone and fabric showed a remarkable improvement of 600% when print materials with different viscosities were applied onto elevated fabric

scholarly journals Methods for the Characterization of Polyetherimide Based Materials Processed by Fused Deposition Modelling

2020 ◽  
Vol 10 (9) ◽  
pp. 3195 ◽  
Author(s):  
Claudio Tosto ◽  
Lorena Saitta ◽  
Eugenio Pergolizzi ◽  
Ignazio Blanco ◽  
Giovanni Celano ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Mechanical Tests ◽  
Fused Deposition Modelling ◽  
Specific Test ◽  
Test Standards ◽  
Fused Deposition ◽  
Structural Applications ◽  
Mechanical Performances ◽  
Manufacturing Technologies

Fused deposition modelling (FDM™) is one of the most promising additive manufacturing technologies and its application in industrial practice is increasingly spreading. Among its successful applications, FDM™ is used in structural applications thanks to the mechanical performances guaranteed by the printed parts. Currently, a shared international standard specifically developed for the testing of FDM™ printed parts is not available. To overcome this limit, we have considered three different tests aimed at characterizing the mechanical properties of technological materials: tensile test (ASTM D638), flexural test (ISO 178) and short-beam shear test (ASTM D2344M). Two aerospace qualified ULTEMTM 9085 resins (i.e., tan and black grades) have been used for printing all specimens by means of an industrial printer (Fortus 400mc). The aim of this research was to improve the understanding of the efficiency of different mechanical tests to characterize materials used for FDM™. For each type of test, the influence on the mechanical properties of the specimen’s materials and geometry was studied using experimental designs. For each test, 22 screening factorial designs were considered and analyzed. The obtained results demonstrated that the use of statistical analysis is recommended to ascertain the real pivotal effects and that specific test standards for FDM™ components are needed to support the development of materials in the additive manufacturing field.

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